Submitted to: Trends in Agricultural Science
Publication Type: Proceedings
Publication Acceptance Date: 12/22/2003
Publication Date: 12/31/2003
Citation: Cheng, H. 2003. Neurophysiologic regulation and animal well-being in poultry laying hens. Trends in Agricultural Science. p. 15. Interpretive Summary: Chronic social stress in chickens reared in high-density environments, such as battery cage system, may be a major problem in the modern poultry industry since social stress has a large impact in both chicken welfare and performance. The present study has revealed that animals' response to social stress is controled by both the peripheral and central nervous systems. These data suggest that the changes of neurotransmitter concentrations can be used as indicators by producers and scientists to evaluate birds' well-being.
Technical Abstract: The modern intensification of the farm animal industry has led to widespread public concern regarding animal well-being and public health. Animal well-being is an indistinct concept and well-being is affected by multiple factors, including both internal and external events, which are regulated at different levels by different stress buffering systems including the nervous system. Genetic basis of different regulation of neuroendocrine changes in response to different stressors were studied in chicken lines divergently selected for high (HGPS) or low (LGPS) group productivity and longevity resulting from changes in cannibalism and flightiness in multiple-hen cages. Compared to HGPS hens, LGPS hens had greater blood concentrations of dopamine and epinephrine (P < .01). Blood concentrations of norepinephrine were not significantly different between the lines but the ratio of epinephrine to norepinephrine was greater in the LGPS hens (P < .01). The blood concentration of serotonin was also greater in the LGPS hens compared to the HGPS hens (P < .01). These results indicate that genetic selection for group productivity and longevity altered the chickens' physiological homeostasis that produced the line's unique coping ability with domestic environments.